Sequential infiltration synthesis apparatus and a method of forming a patterned structure

ABSTRACT

A sequential infiltration synthesis apparatus comprising:
         a reaction chamber constructed and arranged to hold at least a first substrate;   a precursor distribution and removal system to provide to and remove from the reaction chamber a vaporized first or second precursor; and,   a sequence controller operably connected to the precursor distribution and removal system and comprising a memory provided with a program to execute infiltration of an infiltrateable material provided on the substrate when run on the sequence controller by:   activating the precursor distribution and removal system to provide and maintain the first precursor for a first period T 1  in the reaction chamber;   activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T 2 ; and,   activating the precursor distribution and removal system to provide and maintain the second precursor for a third period T 3  in the reaction chamber. The program in the memory is programmed with the first period T 1  longer than the second period T 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, U.S. patentapplication Ser. No. 15/380,921 filed Dec. 15, 2016 titled SEQUENTIALINFILTRATION SYNTHESIS APPARATUS AND A METHOD OF FORMING A PATTERNEDSTRUCTURE, the disclosure of which is hereby incorporated by referencein its entirety.

FIELD OF INVENTION

The present disclosure generally relates to apparatus and methods tomanufacture electronic devices. More particularly, the disclosurerelates to forming a structure or a layer on a substrate with aninfiltration apparatus.

BACKGROUND

As the trend has pushed semiconductor devices to smaller and smallersizes, different patterning techniques have arisen. These techniquesinclude spacer defined quadruple patterning, extreme ultravioletlithography (EUV), and EUV combined with Spacer Defined Doublepatterning. In addition, directed self-assembly (DSA) has beenconsidered as an option for future lithography applications. DSAinvolves the use of block copolymers to define patterns forself-assembly. The block copolymers used may include poly(methylmethacrylate) (PMMA), polystyrene, or poly(styrene-block-methylmethacrylate) (PS-b-PMMA). Other block copolymers may include emerging“high-Chi” polymers, which may potentially enable small dimensions.

The patterning techniques described above may utilize an infiltrateablematerial, such as an EUV polymer or DSA block copolymer resist, disposedon a substrate to enable high resolution patterning of the substrate. Tosatisfy the requirements of both high resolution and line-edgeroughness, the polymer resist may be a thin layer. However, such thinpolymer resists layer may have several drawbacks. In particular, highresolution polymer resists may have low etch resistance and may sufferfrom high line edge roughness. This low etch resistance and the highline edge roughness may make the transfer to underlying layers moredifficult.

It may therefore be advantageous to infiltrate an infiltrateablematerial, for example the patterned material resist, to alter theproperties of the infiltrateable material. To perform infiltration itmay be advantageously to have an infiltration apparatus which may tunethe infiltration process.

SUMMARY

In accordance with at least one embodiment of the invention there isprovided a sequential infiltration apparatus comprising a sequentialinfiltration synthesis apparatus comprising:

a reaction chamber constructed and arranged to hold at least a firstsubstrate;

a precursor distribution and removal system to provide to and removefrom the reaction chamber a gaseous first or second precursor; and,

a sequence controller operably connected to the precursor distributionand removal system and comprising a memory provided with a program toexecute infiltration of an infiltrateable material provided on thesubstrate when run on the sequence controller by:

activating the precursor distribution and removal system to provide andmaintain the first precursor for a first period T1 in the reactionchamber;

activating the precursor distribution and removal system to remove aportion of the first precursor from the reaction chamber for a secondperiod T2; and,

activating the precursor distribution and removal system to provide andmaintain the second precursor for a third period T3 in the reactionchamber. The program in the memory may be programmed with the firstperiod T1 longer than the second period T2. The first period T1 ofproviding the first precursor may be programmed longer than the secondperiod T2 of removing a portion of the first precursor so that the firstprecursor gets enough time to deeply infiltrate the infiltrateablematerial.

The second period T2 may be programmed long enough to remove the firstprecursor from the reaction chamber and also from the surface of theinfiltrateable material to assure that there is only infiltration of thefirst precursor in the infiltrateable material and no significantdeposition on the infiltrateable material.

The second period T2 may be programmed long enough to remove the firstprecursor from the reaction chamber, from the surface of theinfiltrateable material and also, partially, from the pores in theinfiltrateable material. In this way the depth of the infiltration maybe tuned.

In accordance with a further embodiment there is provided a sequentialinfiltration synthesis apparatus comprising:

a reaction chamber constructed and arranged to hold at least a firstsubstrate;

a precursor distribution and removal system to provide to, and removefrom the reaction chamber a vaporized first or second precursor; and,

a sequence controller operably connected to the precursor distributionand removal system and comprising a memory provided with a program toexecute infiltration of an infiltrateable material provided on thesubstrate when run on the sequence controller by:

activating the precursor distribution and removal system to provide andmaintain the first precursor for a first period T1 in the reactionchamber;

activating the precursor distribution and removal system to remove aportion of the first precursor from the reaction chamber for a secondperiod T2; and,

activating the precursor distribution and removal system to provide andmaintain the second precursor for a third period T3 in the reactionchamber.

The program in the memory is programmed to execute during the firstperiod T1:

activating the precursor distribution and removal system to close a gasremoval flow path and provide the first precursor to the reactionchamber for a load period LP; and

activating the precursor distribution and removal system to close thefirst precursor flow path and maintain the first precursor in thereaction chamber while keeping the removal flow path closed for a soakperiod SP. In this way an economical usage of the first precursor can beassured during the long first period that may be necessary for theinfiltration process.

According to a further embodiment there is provided a method of forminga patterned structure or a layer with the sequential infiltrationsynthesis apparatus, wherein the method comprises: providing a substratewith a patterned infiltrateable material on top in a reaction chamber;and,

infiltrating the patterned infiltrateable material with infiltrationmaterial in at least one infiltration cycles. The infiltration cyclecomprises:

activating a precursor distribution and removal system to provide andmaintain a first precursor for a first period T1 in the reactionchamber;

activating the precursor distribution and removal system to remove aportion of the first precursor from the reaction chamber for a secondperiod T2; and,

activating the precursor distribution and removal system to provide andmaintain a second precursor for a third period T3 in the reactionchamber. The first period T1 is longer than the second period T2. Thepatterned infiltrateable material may be a patterned photoresist or DSAmaterial.

The first period T1 may comprise:

closing of a gas removal flow path and provide the first precursor tothe reaction chamber for a load period LP; and

closing the first precursor flow path and maintain the first precursorin the reaction chamber while keeping the removal flow path closed for asoak period SP.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE FIGURES

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

FIG. 1 depicts a sequential infiltration synthesis apparatus accordingto an embodiment.

FIGS. 2a and 2b illustrate an infiltration program in accordance with atleast one embodiment which may be executed by the sequentialinfiltration apparatus of FIG. 1.

FIG. 3 depicts a reaction chamber of a sequential infiltration apparatusaccording to an embodiment.

FIG. 4 depicts a reaction chamber of a sequential infiltration apparatusaccording to a further embodiment.

FIG. 5 depicts a reaction chamber of a sequential infiltration apparatusaccording to an embodiment comprising a batch reactor.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

FIG. 1 depicts a sequential infiltration synthesis apparatus accordingto an embodiment. The apparatus comprises a reaction chamber 2 made of asuitable material such as steel, aluminum or quartz. A substrate 12provided with an infiltrateable material on top may be placed in thereaction chamber 2 on a substrate holder 10 by a substrate handler via asubstrate opening (not shown). The reaction chamber 2 forms a chamberclosed at one end by a flange, through which gases are introduced viaone or more openings provided with at least one (distribution) reactionchamber valve 19 to control opening and closing of said openings. Thedistribution reaction chamber valve 19 provides access of a fluiddistribution portion of the precursor distribution and removal system tothe reaction chamber 2.

The precursor distribution and removal system may provide a first or asecond precursor 28, 29 to the reaction chamber via the distributionreaction chamber valve 19. The first precursor 28 may be introduced as agas into the chamber 2 by evaporating a liquid or solid contained in acontainer 30 by first precursor heater 32 to provide adequate vaporpressure for delivery into the chamber 2. The first precursor heater 32may provide heat to the first precursor in the container 30. Equally asecond precursor 29 may be introduced as a gas into the chamber 2 byevaporating a liquid or solid contained in container 31 by a secondprecursor heater 33 to provide adequate vapor pressure for delivery intothe reaction chamber 2. As depicted the flow paths for the first andsecond precursor may be partially common however they also may bepartially or completely separated. In case of separated flow paths, eachflow path may be provided with a separate distribution reaction chambervalve 19.

The precursor distribution and removal system may comprise a purgesystem to provide a purge gas 34 to the reaction chamber 2 via the purgevalve 24 and the distribution reaction chamber valve 19. The purge gasmay be an inert gas such as nitrogen and may be used to purge thereaction chamber 2. As depicted the flow paths for purge gas, the firstand second precursor may be partially common however they also may bepartially or completely separated. In case of separated flow paths, eachflow path may be provided with a separate distribution reaction chambervalve 19.

Alternatively or additionally, the purge system may be constructed andarranged to provide the purge gas directly in to the reaction chamber 2via a purge reaction chamber valve (not shown) which directly providesthe purge gas in the reaction chamber 2. By providing the purge gasdirectly in the reaction chamber it becomes possible to use theprecursor distribution and removal system to load with precursor whilethe reaction chamber is purged. In this way it becomes possible toincrease throughput.

Optionally, a separate exhaust (not depicted) from precursor duct 18 tothe pump 39 may be used to purge the precursor duct 18 more effectivelywhile the distribution reaction chamber valve 19 is closed.

The reaction chamber may be closed at the other end by a flange whichconnects to a gas removal part of the precursor distribution and removalsystem via one or more openings provided with one or more reactionchamber valves 36, such as e.g. a gate valve. A gas removal pump 39 maybe part of the gas removal portion of the precursor distribution andremoval system.

The reaction chamber 2 may be provided with an opening (not shown) toprovide substrates to the substrate holder 10. A door may be provided toclose and open the opening to provide access by a substrate handler tothe substrate holder 12. The substrate holder may also form part of thereaction chamber 2 and be moveable in a downward direction to provideaccess to the substrate holder 10 by the substrate handler.

The first precursor 28 may be a compound having an element of theinfiltration material to be formed in the infiltrateable material on thesubstrate 12. The first precursor 28 may be provided into the reactionchamber 2 through first precursor valve 20 and distribution reactionchamber valve 19. FIG. 1 illustrates a system with two containers 30 and31, each containing a first and second precursor 28 and 29 respectively.However the type of infiltration material to be formed will determinethe number of precursor and containers. For example, if a ternaryinfiltration material is desired, the apparatus may include threecontainers and three precursor valves. The containers 30 and 31 may bebottles or other sources of precursor as required. For example if one ofthe precursors may be solid there may be provided specially adaptedcontainers to accelerate sublimation of the solid precursor. One of thecontainers 30, 31 may also be provided with a gaseous precursor suchthat heating is not required.

A sequence controller 40 e.g. a microcontroller may be operablyconnected to the one or more reaction chamber valves 19, 36, theprecursor valves 20, 22 and a purge valve 24. The sequence controller 40comprises a memory M for storing a program to enable the apparatus toexecute infiltration of the infiltrateable material provided on thesubstrate 12 in the reaction chamber 2 with the first and secondprecursor 28, 29. A temperature sensor 26 may monitor the reactionchamber temperature. The temperature sensor 26 may be provided with apressure sensor as well. The temperature sensor may be operablyconnected with the sequence controller 40 to optimize the processconditions of the infiltration. The program in the memory M of thesequence controller 40 may be programmed to sequence the opening andclosing of the valves 19, 20, 22, 24 and 36 at the appropriate times toprovide and remove the first and second precursor to the reactionchamber 2.

The apparatus may be provided with a heating system comprising a firstheating element 14 e.g. a heating resistor wire, and a heatingcontroller 16 and may be operably connected to the temperature sensors26. One or more of the temperature sensors 26 may be provided with apressure sensor as well. The heating controller may be operablyconnected to the sequence controller 40. The temperature sensors 26 maybe used to measure the temperature in the reaction chamber 2 and providefeedback to the heating controller 16 about this temperature to adjustthe temperature of the heating element 14 to adjust the temperature ofthe reaction chamber 2. There may be additional temperature sensors tocontrol the temperature in the reaction chamber 2 and/or the precursordistribution and removal system to provide a multi-zone temperaturecontrol in the apparatus.

One or more of the temperature sensors 26 may be provided with apressure sensor as well. The pressure sensor may be operably connectedto the sequence controller 40 to adjust the processing sequence on thebasis of the measured pressure.

A precursor feed flow duct between the (distribution) reaction chambervalve 19 and the reaction chamber 2 may be provided with a portion ofthe heating element 14. This portion of the heating element 14 along theprecursor feed flow duct may be individually controlled with thetemperature sensor 26 extending in the duct and the heating controller16 to adjust the temperature of the precursor feed flow duct.

A precursor removal flow duct between the reaction chamber 2 and the(removal) reaction chamber valve 36 may be provided with a portion ofthe heating element 14. This portion of the heating element 14 along theprecursor removal flow duct may be individually controlled with thetemperature sensor 26 extending in the precursor removal flow duct andthe heating controller 16.

In this way cold spots which may cause condensation in the reactionchamber 2, the precursor feed flow duct and the precursor removal flowduct may be avoided. Condensation of the precursor may cause that theprecursor is not effectively removable out of the reaction chamber intime and therefore the condensate may react with a subsequent precursorforming particles which may contaminate the reaction chamber and thesubstrate 12. Especially particles in the flow path deliveringprecursors may cause many problems.

The temperature may be set to an optimized process temperature. Thespeed of the infiltration process may scale with the pressure and thetime during which the first or second precursor is allowed to infiltratethe infiltrateable material on the substrate: at higher temperatures theinfiltration proceeds faster. Processing at higher pressure is thereforeadvantageous to reduce process time and maximize throughput butincreases the risk of condensation. The optimized process temperatureshould be higher than the boiling temperature of the first or secondprecursor at the maximum pressure of the first or second precursor inthe reaction chamber 2 to avoid condensation. By controlling thetemperature from the reaction chamber 2 up to at least one of thereaction chamber valves 19, 36 the risk of condensation can beminimized.

For example if the first or second precursor is trimethylaluminium (TMA)the vapor pressure is:

20 C˜9 Torr

40 C˜25Torr

60 C˜64 Torr

80 C˜149 Torr

100 C˜313 Torr

128 C˜760 Torr

As can be seen from these values, the processing pressure can beincreased substantially by increasing the temperature in the reactionchamber. However if there is a small portion in the apparatus which incontact with the precursor and which has a slightly lower temperaturethere is an immediate risk of condensation of the precursor which isunwanted.

The interaction of TMA precursor with the infiltrateable material may beprimarily through adsorption and diffusion. The temperature may have asignificant effect on the infiltration because the rate of adsorptionand diffusion and the equilibrium in an adsorption reaction may beimpacted by changes in temperature.

The infiltration process may be optimal at 90° C. while at 120° C. and150° C. the infiltration is less good for TMA. This may be expected foran adsorption based process. At higher temperature the equilibrium ofthe adsorption reaction may shift towards separate TMA and polymerspecies. A process temperature between 20 and 450° C., preferablybetween 50 and 150° C., more preferably between 60 and 110° C. and mostpreferably between 65 and 95° C. is therefore preferred.

The heating system may be constructed and arranged to control thetemperature of the reaction chamber and a duct from the reaction chamberup to at least their respective reaction chamber valves to between 20and 450° C., preferably between 50 and 150° C., more preferably between60 and 110° C. and most preferably between 65 and 95° C. The sequencecontroller may be constructed and arranged to reach and/or maintain apressure of the first or second precursor in the reaction chamberbetween 0.001 and 1000 Torr, preferably between 1 and 400 Torr, morepreferably between 5 and 100 Torr and most preferably between 10 and 50Torr during infiltration to avoid condensation. In this way we create asufficient safety margin to avoid condensation in the apparatus whilehaving an optimum process temperature and pressure with respect to theuse of the precursor TMA.

The apparatus may comprise a direct liquid injector (DLI) comprising aliquid flow controller and a vaporizer. The liquid flow controller maycontrol a liquid flow to a vaporizer to evaporate the first or secondprecursor. There may not be a need to heat the liquid flow between theflow controller and the vaporizer. The vaporizer may be heated toevaporate the first or second precursor. The heating system 16 may beconstructed and arranged to control the temperature from the reactionchamber 2 up to the vaporizer to at least a boiling temperature of thefirst or second precursor at the pressure of the first or secondprecursor in the reaction chamber to avoid condensation. The vaporizermay be constructed and arranged in the reaction chamber to directlyprovide the evaporated precursors in the reaction chamber. The vaporizermay also be constructed and arranged in the precursor distribution andremoval system of the apparatus.

The precursor distribution and removal system may comprise a bubbler forproviding the precursor. The bubbler may provide a non-continuousprecursor flow having pulses of the first precursor of 0.1 to 200,preferably 1 to 3 seconds alternating with pulses of a mixing gas for0.01 to 30, preferably 0.3 to 1 seconds.

Referring to FIG. 1, during a typical operation, the first precursor 28is infiltrated in the infiltrateable material on the substrate byexposure to the first precursor 28 in vapor phase from the container 30.The first precursor 28 may react with the infiltrateable material on thesubstrate and become a chemisorbed or physisorbed derivative infiltratedin the infiltrateable material on the substrate. Subsequently the secondprecursor 29 is infiltrated in the infiltrateable material on thesubstrate by exposure to the second precursor 29 in vapor phase from thecontainer 31. The second precursor 29 may react with the chemisorbed orphysisorbed derivative of the first precursor 28 infiltrated in theinfiltrateable material on the substrate to become the finalinfiltration material.

The containers 30, 31 for storing a first or second precursor may storean alkyl compound of a metal or of boron. The metal may be aluminum andthe alkyl compound may be selected from the group consisting oftrimethyl aluminum (TMA), triethyl aluminum (TEA), anddimethylaluminumhydride (DMAH).

The containers 30, 31 for storing a first or second precursor may storea metal halide compound The metal halide compound may be titanium (IV)chloride (TiCl), tantalum (V) chloride (TaCl5), and/or niobium chloride(NbCl5).

For infiltrating zirconium or hafnium the containers 30, 31 may beconstructed and arranged to store a Zr or Hf precursor. The Zr or Hfprecursor may comprise metalorganic, organometallic or halide precursor.In some embodiments the precursor is a halide, such as Zirconium (IV)chloride (ZrCl4) or HfCl4 Hafnium (IV) chloride. In some otherembodiments the precursor is alkylamine compound of Hf or Zr, such asTEMAZ or TEMAH.

The containers 30, 31 for storing a first or second precursor may storean oxidant chosen from the group comprising oxygen, water, ozone, orhydrogen peroxide, or a nitridizer selected from the group comprisingammonia and hydrazine.

The apparatus may comprise a first container 31 for containing the firstor second precursor such as an aluminum or boron hydrocarbon compoundpreferably selected from the group consisting of trimethyl aluminum(TMA), triethyl aluminum (TEA), and dimethylaluminumhydride (DMAH)dimethylethylaminealane (DMEAA), trimethylaminealane (TEAA),N-methylpyrroridinealane (MPA), tri-isobutylaluminum (TIBA),tritertbutylaluminum (TTBA) trimethylboron and triethylboron and asecond container for containing the other of the first and secondprecursor such as a metal halide preferable from the group consisting oftitanium (IV) chloride (TiCl), tantalum (V) chloride (TaCl5), andniobium chloride (NbCl5). The latter may be preferable for infiltratingmetal carbide material.

FIGS. 2a and 2b illustrate an infiltration method in accordance with atleast one embodiment of the invention for use in the apparatus ofFIG. 1. The method includes a first step 50 of providing a substrateinto a reaction chamber with a substrate handler, the substrate havingat least one infiltrateable material on the substrate.

The infiltrateable material may be porous. Porosity may be measured bymeasuring the void spaces in the infiltrateable material as a fractionof the total volume of the infiltrateable material and may have a valuebetween 0 and 1. The infiltrateable material may be qualified as porousif the fraction of void spaces over the total volume is larger than 0.1,larger than 0.2 or even larger than 0.3.

In an embodiment the infiltrateable material may be a patterned layerfor example a patterned resist layer. The resist layer may be annealed.The anneal step may have a purpose of degassing moisture or othercontaminants from the resist, hardening the resist, selectively burningaway portions of the resist from the substrate surface or creating therequired porosity.

In an embodiment the patterned layer may be provided by having a blockcopolymer film and promoting directed self-assembly of the blockcopolymer film to form the patterned layer. Infiltrating such patternedlayer may improve the quality of such patterned layer. The blockcopolymer film may, for example, have a low etch resistance and byinfiltrating the pattern in the copolymer the etch resistance of thepattern may be improved.

In an embodiment the patterned layer may be provided by having aphotoresist being exposed with a lithographic apparatus. Infiltratingsuch patterned layer may improve the quality of such patterned layer.The patterned photoresist layer may, for example, have a low etchresistance and by infiltrating the patterned photoresist the etchresistance of the pattern may be improved.

After the substrate is positioned in the reaction chamber 2 in FIG. 1during step 50 in FIG. 2a , the reaction chamber and substrate may becleaned by the program in the memory M of the sequence controller 40,making the removal pump 39 to evacuate the reaction chamber 2.Optionally a purge gas 34 may be provided with the purge system to flushthe reaction chamber 2 via the purge valve 24 and the distributionreaction chamber valve 19 and/or the reaction chamber 2 may be heated toenhance outgassing. The program in the memory M may be programmed toactivate the precursor distribution and removal system to remove gasfrom the reaction chamber 2 and to provide purge gas with the purgesystem to have the reaction chamber purged for 1 to 4000 seconds,preferably 100 to 2000 seconds before the infiltration is started. Theprogram in the memory M may be programmed to activate the heater system16 to heat the reaction chamber 2 to a temperature between 20 and 450°C., preferably between 50 and 150° C. and most preferably between 70 and100° C. to enhance outgassing of contaminants.

Subsequently, the memory M of the sequence controller 40 may be providedwith a program which, when executed on the processor of the sequencecontroller 40, makes the infiltration apparatus execute an infiltrationmethod 51 in which the infiltrateable material may be infiltrated withthe infiltration material during one or more infiltration cycles. Eachinfiltration cycle may comprise the following steps:

Step 52 comprises providing a first precursor to the infiltrationmaterial on the substrate in the reaction chamber for a first period T1.The memory M of the sequence controller 40 may be provided with aprogram which, when executed on the processor of the sequence controller40, makes the infiltration apparatus close the purging valve 24 and thedistribution reaction chamber valve 19 and builds up first precursor inthe duct of the precursor distribution and removal system upstream ofthe distribution reaction chamber valve 19 by opening the firstprecursor valve 20 and evaporating the first precursor 28 from the firstcontainer 30 by having the first precursor temperature controller 32activated to heat the container 32. Then the program in the memory M ofthe sequence controller 40 may be programed to open valve 19 for a shortperiod of time to deliver the first precursor 28 to the reactor chamber2.

This may be done with the removal reaction chamber valve 36 opened andthe removal pump activated for a flush period FP to flush the reactionchamber 2 with the first precursor, however this may also be omitted.When the reaction chamber 2 is constructed and arranged to accommodate asingle substrate the program in the memory may be programmed to activatethe precursor distribution and removal system for a flush period FPbetween 1 to 60, preferably between 2 and 30 seconds. When the reactionchamber is constructed and arranged to accommodate 2 to 25 substratesthe program in the memory may be programmed to have the flush periodbetween 1 to 100, preferably between 2 and 50 seconds. When the reactionchamber is constructed and arranged to accommodate 26 to 200 substratesand the program in the memory is programmed to have the flush period FPbetween 1 to 100, preferably between 5 and 50 seconds.

The first precursor may also be provided to the reactor chamber 2 withthe precursor distribution and removal system while not removing anyprecursor with the removal pump 39 for a loading period LP by closingthe removal reaction chamber valve 36 by a program installed in thememory M of the sequence controller 40. This results in a pressurebuildup of the first precursor in the reaction chamber 2. This build upmay be terminated by the sequence controller 40 when the pressure of thefirst or second precursor in the reaction chamber 2 reaches a desiredprocess pressure, preferably between 0.001 and 1000 Torr, preferablybetween 1 and 400 Torr, more preferably between 5 and 100 Torr and mostpreferably between 10 and 50 Torr. Alternatively there may be a pressurerelease valve which opens when the pressure in the reaction chamberincreases above a predetermined desired process pressure which may alsoend the load period LP.

Subsequently, the first precursor may be maintained residing stationaryin the reaction chamber 2 while having the precursor distribution andremoval system not providing or removing any precursor for a soak periodSP. This may be done by the sequence controller 40 closing the reactorchamber valves 19 and 36 in accordance with a program stored in thememory M of the sequence controller 40. When the reaction chamber 12 isconstructed and arranged to accommodate a single substrate the programin the memory M may be programmed to activate the first precursor flowcontroller for the load period LP between 1 to 3000, preferably between3 and 1000, more preferably between 5 to 500 seconds; and the soakperiod SP between 10 to 9000, preferably between 50 and 5000 seconds andmore preferably between 100 and 1000 seconds. When the reaction chamber12 is constructed and arranged to accommodate 2 to 25 substrates theprogram in the memory sequence controller may be programmed with theload period LP between 1 to 3000, preferably between 3 and 1000, morepreferably between 5 to 500 seconds; and the soak period SP between 10to 12000, preferably between 15 and 6000 seconds and more preferablybetween 20 and 1000 seconds. When the reaction chamber 12 is constructedand arranged to accommodate 26 to 200 substrates the program in thememory M may be programmed to have the load period LP between 1 to 3000,preferably between 3 and 1000, more preferably 5 to 500 seconds; and thesoak period SP between 10 to 14000, preferably between 50 and 9000seconds, more preferably between 100 and 5000 and most preferablybetween 100 and 800 seconds.

The first period T1 therefore may comprise a flush period FP, a loadperiod LP, and/or a soak period SP. During the whole period T1 the firstprecursor may infiltrate and absorb in the infiltrateable material. Thememory M of the sequence controller 40 may be programmed with a programwhen executed on a processor of the sequence controller which will makethe infiltration apparatus to provide the first precursor for the firstperiod T1 between 1 to 20000, preferably between 20 to 6000, morepreferably between 50 and 4000, and most preferably between 100 and 2000seconds in step 52. In this way a deep infiltration of the firstprecursor in the infiltrateable material is assured.

In step 53 a portion of the first precursor is removed for a secondperiod T2. The program in the memory M of sequence controller 40 mayopen the removal reaction chamber valve 36 to remove first precursorwith the vacuum pump 38 from the reaction chamber 2. Additionally oralternatively a purge gas 34 may be provided with the purge system toflush the reaction chamber 2 by opening the purge valve 24 and thedistribution reaction chamber valve 19 with the sequence controller 40.

The program in the memory M of the sequence flow controller 40 may beprogrammed with a program when executed on a processor of the sequencecontroller 40 makes the infiltration apparatus to have the duration T1of providing the first precursor to the infiltrateable material longerthan the second duration T2 of removing the portion of the firstprecursor. The program in the memory M may be programmed with the firstperiod T1 between 2 to 10000, preferably between 5 to 2000, morepreferably between 10 to 1000 times longer than the second period of T2.The program in the memory M may be programmed with the second period T2between 0.1 to 3000, preferably between 3 to 100, more preferablybetween 6 to 50, even more preferably between 8 to 30 seconds and mostpreferably between 10 to 25 seconds.

The second period T2 in step 53 may be just sufficient to remove thefirst precursor from the reaction chamber, for example 0.1 to 50preferable 1 to 10 seconds. In this way there is infiltration in theinfiltrateable material and deposition on the infiltrateable material.

Alternatively, the second period T2 may be chosen just long to removethe first precursor from the reaction chamber but also from the surfaceof the infiltrateable material. For example with T2 being 1 to 1000,preferable 8 to 100 seconds there may be only infiltration of the firstprecursor in the infiltrateable material left and no significantdeposition remaining on the surface of the infiltrateable material aftercompletion of step 53.

Alternatively, in step 53 the second period T2 may be chosensufficiently long, for example 2 to 3000 preferable 30 to 100 seconds toremove the first precursor from the reaction chamber, from the surfaceof the infiltrateable material and also for a part from the infiltratedfirst precursor in the infiltrateable material. In this way the depth ofthe infiltration may be tuned effecting the line width reduction.

The reaction chamber 2 may be constructed and arranged to accommodate asingle substrate and the program in the memory M may be programmed withthe first period T1 between 2 to 6000 preferably between 4 to 100 andmost preferably between 8 to 50 times longer than the second period T2.The first period T1 for such reaction chamber may be between 1 to 20000,preferably between 20 to 4000, more preferably between 30 and 1000seconds.

The reaction chamber 2 may be constructed and arranged to accommodate 2to 25 substrates and the program in the memory M may be programmed withthe first period T1 between 2 to 8000 preferably between 10 to 500 andmost preferably between 20 to 200 times longer than the second periodT2. The first period T1 for such reaction chamber may be between 1 to16000, preferably between 20 to 7000, more preferably between 30 and1500 seconds.

The reaction chamber 2 may be constructed and arranged to accommodate 26to 200 substrates and the program in the memory M may be programmed withthe first period T1 between 2 to 10000, preferably between 10 to 2000,more preferably between 20 to 1000 times longer than the second periodT2. The first period T1 for such reaction chamber 12 may be between 1 to20000, preferably between 100 to 10000, more preferably between 200 and6000 and most preferably between 300 and 4000 seconds.

In step 54 the second precursor is provided in the reaction chamber 2 bythe sequence controller 40 activating the precursor distribution andremoval system to provide and maintain the second precursor for a thirdduration T3 in the reaction chamber. The program in the memory M may beprogrammed with the third period T3 between 1 to 20000, preferablybetween 5 and 5000 and most preferably between 10 and 2000 seconds.

The memory of the sequence controller 40 may be programmed to close thepurging valve 24 and the distribution reaction chamber valve 19 andbuilding up second precursor in the duct of the precursor distributionand removal system upstream of the distribution reaction chamber valve19 by opening the second precursor valve 22 and evaporating the secondprecursor 29 from the second container 31 by heating the secondcontainer 31. Then the program in the memory M of the sequencecontroller 40 may be programmed to open valve 19 for a period of time todeliver the second precursor 28 to the reactor chamber 2.

The flush period FP, load period LP, and soak period SP have beendescribed in conjunction with the first precursor. The memory of thesequence controller may be provided with a program when executed on theprocessor of the sequence controller 40 which will make the infiltrationapparatus run the third period T3 with a flush period FP, a load periodLP, and or a soak period SP as well. During the whole third period T3the second precursor may infiltrate the infiltrateable material andreact with the absorbed first precursor derivative in the infiltrateablematerial, resulting in a reinforcement of the infiltrateable materialwith infiltrated material.

Optionally the infiltration cycle may have a step 55 in which a portionof the second precursor may be removed for a fourth period T4. Thesequence controller 40 may open the removal reaction chamber valve 36 toremove second precursor with the vacuum pump 38 from the reactionchamber 2. Additionally or alternatively a purge gas 34 may be providedwith the purge system to flush the reaction chamber 2 by opening thepurge valve 24 and the distribution reaction chamber valve 19 with thesequence controller 40. The fourth period T4 may be between 0.1 to 3000,preferably between 10 to 500, more preferably between 30 to 250 and mostpreferably between 60 to 200 seconds.

The program M may be programed so that when the program is executed on aprocessor of the sequence controller 40 of an infiltration apparatus theinfiltration sequence may be repeated in a loop 56 N times, wherein N isbetween 1 to 60, preferably 3 to 20 and most preferably between 5 to 12.

The precursors 28 and 29 may be chosen such that the precursors form ametal or dielectric infiltration material in the infiltrateablematerial. The precursors are vaporized and preferably gaseous duringinfiltration.

The first precursor and the second precursor may be utilized together inthe apparatus of FIG. 1 to infiltrate the infiltrateable materialaccording to the program of FIGS. 2a and 2b with aluminum oxide (Al2O3),silicon oxide, (SiO2), silicon nitride (SiN), silicon oxynitride (SiON),silicon carbonitride (SiCN), silicon carbide (SiC), titanium carbide(TiC), aluminum nitride (AlN), titanium nitride (TiN), tantalum nitride(TaN), tungsten (W), cobalt (Co), titanium oxide (TiO2), tantalum oxide(Ta2O5), zirconium oxide (ZrO2), or hafnium oxide (HfO2).

Optionally, the infiltration material such as a metal or dielectric maybe deposed on top of the whole volume of the infiltrateable materialwith the infiltration apparatus as well. This may, for example, be doneif the infiltrateable material is patterned to make the pattern widerand more etch resistant.

A patterned structure may be produced with the sequential infiltrationsynthesis apparatus of FIG. 1 by providing a substrate with a patternedinfiltrateable material on top in a the reaction chamber 12 and,infiltrating the patterned infiltrateable material with infiltrationmaterial in at least one infiltration cycle. The patternedinfiltrateable material may be a patterned photoresist or DSA material.The substrate may have a hardmask between the substrate and thepatterned infiltrateable material. The hardmask may be a spin on glass,a spin on carbon, a silicon nitride layer, an anti-reflective-coating,an amorphous carbon, and/or a chemical vapor deposited (CVD) layer (e.g.SIOC or amorphous carbon layer).

While the substrate remains in the sequential infiltration synthesisapparatus the infiltrateable material may be removed while allowing theinfiltration material to remain on the substrate. The infiltrateablematerial may be removed by heating the infiltrateable material to atemperature between 80 and 600° C., preferably 100 to 400° C. and mostpreferably between 120 and 300° C. This allows a reduction of thelinewidth or the linewidth roughness of the patterned structures ofinfiltration material with respect to the patterned infiltrateablematerial.

The infiltrateable material may also be removed by providing a plasma toremove the infiltrateable material in the reaction chamber. An oxygen orhydrogen containing plasma may be used to remove a portion of theinfiltrateable material and may utilize a plasma generator to exciteoxygen species for effective removal of portions of the infiltrateablematerial. The plasma generator may be supplied with oxygen (O2) orhydrogen (H2), or alternatively a gas mixture of hydrogen (H2) or oxygen(O2) and nitrogen (N2). The etchant for removing a portion of theinfiltrateable material may therefore comprise at least one of oxygenexcited species or nitrogen excited species.

FIG. 3 depicts a sequential infiltration apparatus according to afurther embodiment. The precursor distribution and removal systemprovides the first or second precursors from one side of the reactionchamber 2 via entry port 66. The entry port may be closeable with valve19. An exit port 67 is provided to the distribution and removal systemto remove the precursor from the reaction chamber 2.

The substrate holder 10 for holding the substrate 12 may be moveable upand down. The substrate holder 10 may be moveable underneath an edge 68of the top portion of the reaction chamber 2 to allow a substratehandler (not depicted) to provide or remove a substrate from thesubstrate holder 10. By moving it up the reaction chamber can be closedagain. The substrate holder 10 may comprise a third heating element forheating of the substrate 12.

An advantage of the embodiment according to FIG. 3 is that the reactionchamber 2 may have a small volume of 0.5-1 liter for a single substratereaction chamber 2. The small volume making it possible to have a lowprecursor usage. The space between substrate and the top of the reactionchamber may therefore be less than 1 centimeter, preferably less than 5mm and most preferably less than 3 mm.

FIG. 4 depicts a sequential infiltration apparatus according to afurther embodiment. The reaction chamber 2 comprises a showerhead 69.The showerhead 69 may be provided in the top portion of the reactionchamber 2. The showerhead 61 may be connected with the precursordistribution and removal system to provide the first or secondprecursors 28, 29 to the surface of the substrate 12. The precursordistribution and removal system may remove the first or secondprecursors 28, 29 by the opening 67. The purge system may also beconnected to the showerhead 69 to purge the reaction chamber 2.

The showerhead 69 may also be connected with the precursor distributionand removal system to remove the first or second precursors from thereaction chamber 2. The opening 67 may be connected to the purge systemto purge the reaction chamber 2 in such case.

The substrate holder 10 for holding the substrate 12 may be moveable upand down. The substrate holder 10 may comprise a third heating element(not shown) for heating of the substrate 12. An advantage of thisembodiment is that the showerhead rapidly provides and removes precursorfrom the surface of the substrate while the volume still is acceptablebetween 2 to 5 liter, preferably 3 to 4 liter.

FIG. 5 depicts a sequential infiltration apparatus according to afurther embodiment. The apparatus comprises a batch reactor chamber 70for 25 to 250 substrates with a volume of 50-200 liter. The substratesmay be loaded in a boat 71 which is provided with substrate holders toaccommodate the 25 to 250 substrates with a substrate handler. The boat71 with the substrates may be moved into the reaction chamber 70 in oneloading operation, by elevating the boat into the reaction chamberthrough an opening at the lower end of the reaction chamber. The bottompart 71A of the boat 70 may seal the reaction chamber 70. A heatingelement 40 may be provided to control the temperature of the reactionchamber 70. First and second precursor may be provided with the inlet 72and may be removed via outlet 73 of the precursor distribution andremoval system. Valves may be used to control the gas flow and careshould be taken to ensure that the evaporated precursors are kept at atemperature above their boiling temperature in the reaction chamber 70.This may be done by having the heating element to control thetemperature in the inlet 72 and the outlet 73 as well up to the valves(e.g. reaction chamber valve 36).

In case the apparatus is provided with a direct liquid injection system(DLI) comprising a liquid flow controller and a vaporizer, the liquidflow controller may control a liquid flow to the vaporizer whichevaporates the first or second precursor. There may not be a need toheat the liquid flow between the flow controller and the vaporizer. Thevaporizer may be heated to evaporate the first or second precursordirectly.

The vaporizer may be provided in the batch reactor chamber to directlyprovide the first or second precursor in the chamber. A batch reactormakes it possible to infiltrate a large number of substrates at the sametime improving the throughput of the apparatus.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail. Furthermore, the connecting lines shown in the various figuresare intended to represent exemplary functional relationships and/orphysical couplings between the various elements. Many alternative oradditional functional relationship or physical connections may bepresent in the practical system, and/or may be absent in someembodiments.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

The subject matter of the present disclosure includes all novel andnonobvious combinations and sub combinations of the various processes,systems, and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

What is claimed is:
 1. A method of forming a patterned structure with asequential infiltration synthesis apparatus, the method comprising:providing a sequential infiltration synthesis apparatus comprising: areaction chamber constructed and arranged to hold at least a firstsubstrate; a precursor distribution and removal system to provide to andremove from the reaction chamber a vaporized first or second precursor;and, a sequence controller operably connected to the precursordistribution and removal system and comprising a memory provided with aprogram to execute infiltration of an infiltrateable material providedon the substrate when run on the sequence controller by: activating theprecursor distribution and removal system to provide and maintain thefirst precursor for a first period T1 in the reaction chamber;activating the precursor distribution and removal system to remove aportion of the first precursor from the reaction chamber for a secondperiod T2; and, activating the precursor distribution and removal systemto provide and maintain the second precursor for a third period T3 inthe reaction chamber, wherein the program in the memory is programmedwith the first period T1 longer than the second period T2; providing asubstrate with a patterned infiltrateable material in the reactionchamber; and, infiltrating the patterned infiltrateable material withinfiltration material in at least one infiltration cycle.
 2. The methodaccording to claim 1, wherein the substrate comprises a hardmaskcomprising a spin on glass or spin on carbon between the substrate andthe patterned infiltrateable material.
 3. The method according to claim1, wherein the substrate comprises a hardmask comprising a siliconnitride layer between the substrate and the patterned infiltrateablematerial.
 4. The method according to claim 1, wherein the substratecomprises a hardmask comprising an anti-reflective-coating on thesubstrate between the substrate and the patterned infiltrateablematerial.
 5. The method according to claim 1, wherein the substratecomprises a hardmask comprising an amorphous carbon film on thesubstrate between the substrate and the patterned infiltrateablematerial.
 6. The method according to claim 1, wherein the substratecomprises a hardmask comprising a chemical vapor deposited (CVD) layerbetween the substrate and the patterned infiltrateable material.
 7. Themethod according to claim 1, wherein the method comprises while thesubstrate remains in the sequential infiltration synthesis systemremoving the infiltrateable material while allowing the infiltrationmaterial to remain on the substrate.
 8. The method according to claim 7,wherein removing the infiltrateable material comprises heating theinfiltrateable material to a temperature between 80 and 600° C.,preferably 100 to 400° C. and most preferably between 120 and 300° C. 9.The method according to claim 7, wherein the method allows a reductionof the linewidth or the linewidth roughness of the patterned structuresof infiltration material with respect to the patterned infiltrateablematerial.
 10. The method according to claim 7, wherein removing theinfiltrateable material comprises providing a plasma to remove theinfiltrateable material in the reaction chamber.
 11. The methodaccording to claim 1, wherein the patterned infiltrateable materialcomprises a patterned photoresist or DSA material.